Electronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some interface devices, kinesthetic feedback (such as active and resistive force feedback) and/or tactile feedback (such as vibration, texture, and heat) is also provided to the user, more generally known collectively as “haptic feedback” or “haptic effects”. Haptic feedback can provide cues that enhance and simplify the user interface. Specifically, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices to alert the user to specific events, or provide realistic feedback to create greater sensory immersion within a simulated or virtual environment.
In order to generate vibration effects, many devices utilize some type of actuator or haptic output device. Known haptic output devices used for this purpose include an electromagnetic actuator such as an Eccentric Rotating Mass (“ERM”) in which an eccentric mass is moved by a motor, a Linear Resonant Actuator (“LRA”) in which a mass attached to a spring is driven back and forth, or a “smart material” such as piezoelectric, electro-active polymers or shape memory alloys. Haptic output devices also broadly include non-mechanical or non-vibratory devices such as those that use electrostatic friction (“ESF”), ultrasonic surface friction (“USF”), or those that induce acoustic radiation pressure with an ultrasonic haptic transducer, or those that use a haptic substrate and a flexible or deformable surface, or those that provide projected haptic output such as a puff of air using an air jet, and so on.
Within the film and television industries, improved multi-channel audio systems have been developed in order to provide a more engaging experience for viewers. For example, an analog six channel surround sound multichannel audio system referred to as “5.1” was first developed by Dolby Laboratories, Inc., for 70 mm theatrical film screenings, providing three screen channels, two surround channels and a low-frequency enhancement channel. Later, a digital version of 5.1 multi-channel audio referred to as “Dolby Digital” was developed for 35 mm film, and, subsequently, a similar 5.1 system was developed by DTS, Inc. Since then, various multi-channel audio formats have been developed to include 6.1, or 7.1 source material and output up to 11.1 channels and beyond, and multi-channel audio is now included with almost all DVD, Blu-ray, broadcast and streaming video content for home viewing.
With the development of recent high resolution mobile devices such as smart phones and tablets, users are now able to view high definition audio and video on a handheld device that traditionally could only be seen in movie theaters, television or home theater systems. With haptically enabled mobile devices, experience has shown that content viewing is sufficiently enhanced, and viewers like it, if there is a haptic content component in addition to the audio and video content components.